Pumped-storage hydroelectricity (PSH), or pumped hydroelectric energy storage (PHES), is a type of hydroelectric energy storage used by electric power systems for load balancing. The method stores energy in the form of gravitational potential energy of water, pumped from a lower elevation reservoir to a higher elevation. Low-cost surplus off-peak electric power is typically used to run the pumps. During periods of high electrical demand, the stored water is released through turbines to produce electric power. Although the losses of the pumping process make the plant a net consumer of energy overall, the system increases revenue by selling more electricity during periods of peak demand, when electricity prices are highest. If the upper lake collects significant rainfall or is fed by a river then the plant may be a net energy producer in the manner of a traditional hydroelectric plant.
Hydroelectricity, or hydroelectric power, is electricity generated from hydropower. Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined and also more than nuclear power. Hydropower can provide large amounts of low-carbon electricity on demand, making it a key element for creating secure and clean electricity supply systems. A hydroelectric power station that has a dam and reservoir is a flexible source, since the amount of electricity produced can be increased or decreased in seconds or minutes in response to varying electricity demand. Once a hydroelectric complex is constructed, it produces no direct waste, and almost always emits considerably less greenhouse gas than fossil fuel-powered energy plants. However, when constructed in lowland rainforest areas, where part of the forest is inundated, substantial amounts of greenhouse gases may be emitted.
Smith Mountain Lake is a large reservoir in the Roanoke Region of Virginia, United States, located southeast of the City of Roanoke and southwest of Lynchburg. The lake was created in 1963 by the Smith Mountain Dam impounding the Roanoke River. The majority of the south shore of the lake lies in Franklin County while a small portion, including access to the dam, lies in Pittsylvania County. Bedford County makes up the northern half of the lake with the Roanoke River as the dividing line. The lake has become a popular recreation spot and has also experienced significant development in the last decade. It is the largest lake contained entirely within the Commonwealth of Virginia.
The Shoalhaven Scheme is a dual-purpose water supply and Pumped-storage Hydroelectricity scheme located on the South Coast region of New South Wales, Australia.
The Tumut Hydroelectric Power Stations is a series of three hydroelectric power stations on the Tumut River in New South Wales, Australia, that are part of the Snowy Mountains Scheme.
The Robert Moses Niagara Hydroelectric Power Station is a hydroelectric power station in Lewiston, New York, near Niagara Falls. Owned and operated by the New York Power Authority (NYPA), the plant diverts water from the Niagara River above Niagara Falls and returns the water into the lower portion of the river near Lake Ontario. It uses 13 generators at an installed capacity of 2,525 MW (3,386,000 hp).
Leesville Lake is a reservoir in Virginia used for hydroelectric power generation in conjunction with Smith Mountain Lake as a pump storage project. It is located southeast of Roanoke, and southwest of Lynchburg.
Talbingo Dam is a major ungated rock fill with clay core embankment dam with concrete chute spillway across the Tumut River upstream of Talbingo in the Snowy Mountains region of New South Wales, Australia. The impounded reservoir is called Talbingo Reservoir.
Hiwassee Dam is a hydroelectric dam on the Hiwassee River in Cherokee County, in the U.S. state of North Carolina. It is one of three dams on the river owned and operated by the Tennessee Valley Authority, which built the dam in the late 1930s to bring flood control and electricity to the region. The dam impounds the Hiwassee Lake of 6,000 acres (2,400 ha), and its tailwaters are part of Apalachia Lake. At 307 feet (94 m), Hiwassee Dam is the third highest dam in the TVA system, behind only Fontana and Watauga. The dam and associated infrastructure was listed on the National Register of Historic Places in 2017.
Richard B. Russell Dam is a concrete-gravity and embankment dam located on the Savannah River at the border of South Carolina and Georgia, creating Richard B. Russell Lake. The dam was built by the U.S. Army Corps of Engineers between 1974 and 1985 for the purposes of flood control, hydroelectricity, recreation, additional stream flow regulation, water supply, and fish and wildlife management. The concrete structure of the dam spans 1,904 feet (580 m) and rises 210 feet (64 m) above the riverbed, housing a hydro-power plant with an installed 600 megawatts (800,000 hp) capacity. The Richard B. Russell Dam is the final large dam completed by the U.S. Army Corps in the Savannah River Basin and lies 30 miles downstream from the Hartwell Dam (1962) and 37 miles (60 km) upstream from the J. Strom Thurmond Dam (1954).
The Cruachan Power Station is a pumped-storage hydroelectric power station in Argyll and Bute, Scotland. The scheme can provide 440 MW of power and produced 705 GWh in 2009.
The Kölnbrein Dam is an arch dam in the Hohe Tauern range within Carinthia, Austria. It was constructed between 1971 and 1979 and at 200 metres (660 ft) high, it is the tallest dam in Austria. The dam's reservoir serves as the primary storage in a three-stage pumped-storage power system that consists of nine dams, four hydroelectric power plants and a series of pipeline and penstocks. The complex is owned by Verbund power company and is referred to as the Malta-Reisseck Power Plant Group. The installed capacity of the group is 1,028.5 MW and its annual generation is 1,216 gigawatt-hours (4,380 TJ).
The Koyna Hydroelectric Project is the largest hydroelectric power plant in India, just after the Tehri Dam Project. It is a complex project with four dams including the largest dam on the Koyna River, Maharashtra hence the name Koyna Hydroelectric Project. The project site is in Satara district.
The Yangyang Pumped Storage Power Station uses the water of the Namdae-Chun River to operate a 1,000-megawatt (1,300,000 hp) pumped storage hydroelectric power scheme, about 10 kilometres (6.2 mi) west of Yangyang in Gangwon Province, South Korea. The lower reservoir is created by the Yangyang Dam on the Namdae and the upper reservoir by the Inje Dam is located 937 metres (3,074 ft) above the power plant. Construction on the power plant began in 1996 and it was completed and dedicated on September 13, 2006. It is operated by Korean Midland Power Co., a subsidiary of Korea Electric Power Company and was completed at a cost of ₩1.1 trillion won. The first generator was operational on February 23, 2006 and the last August 10, 2006.
The Minghu Dam (Chinese: 明湖水壩; pinyin: Mínghú Shuǐbà, renamed the Takuan Dam, is a concrete gravity dam on the Shuili River located 7 km north of Shuili Township in Nantou County, Taiwan. The reservoir formed by the dam serves as the lower reservoir for the Minhu Pumped Storage Hydro Power Station. Sun Moon Lake serves as the upper reservoir.
The Okuyoshino Pumped Storage Power Station (奥吉野発電所) is located 15 kilometres (9.3 mi) north of Totsukawa in Nara Prefecture, Japan. Using the pumped-storage hydroelectric method, the power plant has an installed capacity of 1,206 megawatts (1,617,000 hp). To accomplish power generation, the power station shifts water between two reservoirs, the lower Asahi Reservoir and the upper Seto Reservoir. Construction on both the Asahi and Seto Dams began in 1971 and was complete in 1978. The power station was commissioned in 1980. Due to heavy sediment and turbidity in the Seto Reservoir, caused by logging and landslides upstream, a sediment bypass tunnel was constructed between 1992 and 1998.
The Edolo Pumped Storage Plant is located along the Oglio River just downstream of Edolo, Brescia Province in the Lombardy region of Italy. Using the pumped-storage hydroelectric method, it has an installed capacity of 1,000 megawatts (1,300,000 hp). Its generators were commissioned between April 1984 and November 1985. Lake Avio was previously completed in 1929 and Lake Benedetto completed in 1940.
The Rocky Mountain Hydroelectric Plant is a pumped-storage power plant located 10 miles (16 km) northwest of Rome in the U.S. state of Georgia. It is named after Rock Mountain on top of which the plant's upper reservoir is located. Construction on the plant began in 1977 and it was commissioned in 1995. After upgrades were completed in 2011, the plant has an installed capacity of 1,095 megawatts (1,468,000 hp). It is owned by both Oglethorpe Power and Georgia Power which have 75 percent and 25 percent stakes, respectively.
Guthega Dam is concrete gravity dam with an uncontrolled spillway across the Snowy River in the Snowy Mountains of New South Wales, Australia. The dam's main purpose is for the storage of water used in the generation of hydro-power. It is the first to be completed of the sixteen major dams of the Snowy Mountains Scheme, a vast hydroelectricity and irrigation complex constructed in south-east Australia between 1949 and 1974 and now run by Snowy Hydro.
The Yixing Pumped Storage Power Station is a pumped-storage hydroelectric power station located Yixing city of Jiangsu Province, China. Construction on the power station began in 2003 and the first unit was commissioned in 2007, the last in 2008. The entire project cost US$490 million, of which US$145 million was provided by the World Bank. The power station operates by shifting water between an upper and lower reservoir to generate electricity. The lower reservoir was formed with the existing Huiwu Dam at the foot of Mount Tongguan. The Yixing Upper Reservoir is located atop Mount Tongguan which peaks at 530 metres (1,740 ft) above sea level. During periods of low energy demand, such as at night, water is pumped from Huiwu Lower Reservoir up to the upper reservoir. When energy demand is high, the water is released back down to the lower reservoir but the pump turbines that pumped the water up now reverse mode and serve as generators to produce electricity. Water from the nearby Huangtong River can also be pumped into the lower reservoir to augment storage. The process is repeated as necessary and the plant serves as a peaking power plant. The power station is operated by East China Yixing Pumped Storage Co Ltd.
